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car stutters and idles weird

Hey i have a 1996 g20, and for awhile now when the car is just idiling the rpm starts to bob up and down, almost stalling, when i start driving in the lower rews it starts to stutter, when you go past 2 rpm it drives fine, a guy told me it might be the idle control vavle, i changed it and its still the same, anybody know what it might be?

I have a 93 mt g20 with the same problem, i was also about to change out the throttle position sensor as you did here in a few weeks. It's sad to hear that you changing it out didn't help, but i'm also planning on hooking up my car to a computer just to see if it says anything. I recently put quite a bit of money into the engine of this car and nothing has worked for that particular problem, but if i find out anything i'll keep you posted.

One thing I have learned reading all the posts on the forum is that all of our cars generally have the same problems eventually and it takes some time, money, and if you do it yourself like i do alot of trial and error.

Could quite possibly be a MAF issue...I honestly have this same general issue, and when I dynoed my car in novemeber it proved to be the handy dandy ebay MAF unit that I purchased that was giving me a fluctuating a/f mix ranging from 15 all the way down to 9 psi. You might trying getting some carb/maf cleaner and giving that a shot. Gl regardless

I have run FI/carb cleaner through the tank and cleaned the carb with cleaner myself a few weeks before. Since i haven't yet replaced the TPS but if i go w the MAF its gunna be the same price. Ive heard a few people on here say it could be IACV but haven't seen anything about results. Advice? Broke and really not wanting to spend a check on IACV

my car has the same problem just like everyone else, i replaced both, the iacv and the idle control valve, whatever their called , i replaced both the units under and on the side of the intake manifold, it didn't fix the problem all the way but the idle did get better and the car wouldn't die after i started it.

instead of fluctuating from 1200 rpm to 800 rpm, it would be 1000 rpm to 800 rpm.

I've also tired unplugging the o2 sensor and i started the car and i noticed my car idled better with it unplugged, i haven't got around to changing it yet but, it did make a difference when i unplugged it.

Also, i don't know if you guys have this problem, but when i drive at night and turn on my headlights my idle drops lower, and when i turn on the defroster it even goes lower.

my car has the same problem just like everyone else, i replaced both, the iacv and the idle control valve, whatever their called , i replaced both the units under and on the side of the intake manifold, it didn't fix the problem all the way but the idle did get better and the car wouldn't die after i started it.

instead of fluctuating from 1200 rpm to 800 rpm, it would be 1000 rpm to 800 rpm.

I've also tired unplugging the o2 sensor and i started the car and i noticed my car idled better with it unplugged, i haven't got around to changing it yet but, it did make a difference when i unplugged it.

Also, i don't know if you guys have this problem, but when i drive at night and turn on my headlights my idle drops lower, and when i turn on the defroster it even goes lower.

I suffer from the same exact symptoms...

I conected my nissan datascan and turned off one of my cylinders and saw no change. swapped spark plugs and there's no prob with them...swapped plug wires and there's no problem there. i guess i must have a bad injector or something like that. But I do wonder about the change when i have the headlights and defroster on, even worst with those two and the heater.

I have the same problem,, idels weard, and if light on it gets worse,, so i replaced the iacv, it worked fine for a wile, and now its back again,, so tomorow, ill replace the distribuitor, the air flow sensor, and idle control valve, and we will see

I conected my nissan datascan and turned off one of my cylinders and saw no change. swapped spark plugs and there's no prob with them...swapped plug wires and there's no problem there. i guess i must have a bad injector or something like that. But I do wonder about the change when i have the headlights and defroster on, even worst with those two and the heater.

Both mine and xnotedgeanymorex's P10s had a bad injector. Replaced the plugs, wires, dist. cap, and button. After that, started pulling plugs out one at a time and found which cylinder it was. It's a bitch pulling out injectors, just so you know. Vice grips are your friend.

Try testing your injectors... in the FSM it says to take your multi-meter and test the injector with your key off. Test in ohms and it should read 10-17 ohms (if I remember correctly). that will let you know if you have a bad injector. If thats good (keep in mind the injector still could be leaking) then just test your voltage going to it. I hope that helps...

I can tell you know that the Iac was not a correct recomendation becuase when on the gas it would have resolved its self meaning you know longer need a step motor to cotroll air volume as you have opened up the throtle eliminating such a posibility.
i dont think you need a maf but it could requior cleaning as only if element has been found to be dirty If not leave it be.
doese your car have an ses are check engine light? if so present the codes. replaceing parts just for the hell of it is not a good idea. the tps if replaced and not calibrated can cuase many new problems makeing your car feel like a money pit. if you have a obd2 scaner with live data I would like to know are if you know a compitant machanic are a technition they should own this. their is a few their are things that it can monitor that can find the exact problem with testing under low load with closed loop fuel control in affect many things can happen but when in open loop higer rpm high load and no problem that tells you something. cuase this works on progamed feed back and know longer uses o2 sesor feed back snd sll the othe remisions stf tat runs on closed lupe control. cant be the fuel pump are cloged filter cuase at hoger rpm where fuel demands are grater you are not haveing the problem. the problem could be as simple as a spark change are a cap are a rotor cuaould be an insuficant ground cuold be tons of stuff but an Iac valve is not even a posibility wick was a poor recomendation based on what you explianed iac can only affect ido quality are also can affect starting than stalling till egine is warm do to build up makeing it stick not allowing air in even thought the ecu comands the valve to do its job. the comand is only as good as the pat ou send it to.
keep in mind your car only hass the problem when you are in closed loop fuel controll than keep in mind what sesors take place In that. the values you are getting can spoof the ecu into injecting less are more fuel than needed cuase they are programed to see a value and react from it. if the value is incorrect than your ecu will create trims that are incorrect and make problems for the drivability in closed loop fuelling
what i can offer is help in understandn ho you car and ecu work. if you can do tests i can help you figure this out with out just replaceing 400$ worrth of sesors under the hood.
but like others said you could have a vac leak depending on size the open lloop enrichment programed be the car might be enough o make the car feel kick ass when it makes the transition. i under stand most people want to here soe one say replace this cuase it is always a problem but it is really not just as simple as that. you will creat more problems trying to fix a car that way. replaceing all parts with new is not a good way to fix A it cost money and B if the new part is not good you are infor a whole new challencg.

man, I have these same symptoms and my CEL came on and when I checked the intake accordian looking thing, it's cracked! going to hit up the junkyard and get a new one....well a non cracked one! and i'll see where it goes from there. . .

After all the struggles it was a bad injector for me. Not sure what was wrong with it, but had a lack in pressure at idle, but when I gunned it it would go. Replaced the injector and called it a day, not as easy as it sounds in a lowport though.

I had a similar problem with my SE-R. I cleaned out all those things and it improved it a little but I still had the same problem. I replaced the O2 sensor and it corrected the issue for me. I know my O2 sensor wasnt replaced in a looong time so I figured it needed it anyway since my milage wasnt great. It might be worth a shot but dont know if it will help...

I had a similar problem with my SE-R. I cleaned out all those things and it improved it a little but I still had the same problem. I replaced the O2 sensor and it corrected the issue for me. I know my O2 sensor wasnt replaced in a looong time so I figured it needed it anyway since my milage wasnt great. It might be worth a shot but dont know if it will help...

My steering wheel will shake some when in idle, but as soon as I start driving or put it in P/N it stops.

So it might be the MAF? Which is?

I don't know that the MAF would cause your sterring wheel to shake at a stop. I'm guessing this is more of a motor mount problem? Your MAF is the "mass air flow" sensor. That's all I know of the MAF, I think it regulates how much air comes in . . .but then so does the IACV. . man I just confused myself. lol

I have been having the same problems on and off on my car, changed the distributor cap and the spinner in side plus plug wires. to day I changed the fuel pump to a Walbro GSS 341, and fuel filter, everything felt a little bit better, but not good so tomorrow I'm changing over to the old fuel rail from the old engine.
btw got the SR20De (EDM) primera 94.